Single axis combined ion and vapor source

Abstract

Combining an evaporation source and an ion beam source to provide a crucible anode surface, and heating that crucible anode surface to a high enough temperature to cause evaporation of anode material, provides for emission of atoms and ions selectively and independently controllable and directed along the identical path. A high melting point material auxiliary anode, connected to the crucible anode by a variable resistance, provides independent control of the vapor flux by selectively shifting the discharge current from auxiliary anode to crucible anode. The crucible anode contains the material which is to be evaporated. A gas plasma discharge is supplied between a heated cathode filament and the heated crucible anode. Electrons carrying a discharge current bombard the crucible anode material surface, causing a temperature rise which causes an increase in discharge current. At a high enough discharge current level, the anode material in the crucible anode melts and vaporizes, forming a stream which passes through an extraction grid to deposit vaporized anode material on a substrate. The gas discharge generates ions, which are accelerated by voltages on the anodes, forming an ion beam which also strikes the substrate. The flux of the ion beam is controlled by the discharge current. The ion energy is controlled by the anode power supply. Shifting a portion of the discharge current from the auxiliary anode to the crucible anode increases the amount of vapor flux for a given ion flux.

1.  Apparatus for generating both vapor flux and ion flux--characterized by-- (a) flux generating means, for simultaneously generating an ion flux and a vapor flux from a common source; and   (b) control means, for varying the amount of said vapor flux for a given ion flux.   
     
     
       2. Apparatus for generating both vapor flux and ion flux, according to claim 1 --further characterized in that--   said control means comprises an auxiliary anode coacting with said flux generating means and comprises current control means in circuit with said auxiliary anode.   
     
     
       3. A single axis combined ion and vapor source having power sources including a dc power source, a heated cathode, an anode source of ionizable material and a distribution port for distributing ions and vapor of such ionizable material to a target--characterized by-- (a) an auxiliary anode physically located in the vicinity of such anode source;   (b) a variable resistance electrically connected to said auxiliary anode; and   (c) power connecting means connecting the anode source and said variable resistance to the dc power source;   whereby manipulation of said variable resistance device alters the voltage relationship between such anode source and said auxiliary anode and thereby alters the discharge current division, diverting selective amounts of discharge current to said auxiliary anode resulting in altered heating of the anode source, so as to vaporize selective amounts of the anode material of such anode source, thereby providing selective control of vapor flux for a given ion flux.   
     
     
       4. A single axis combined ion and vapor source according to claim 3, --further characterized in that--   such anode source in turn comprises crucible anode means and anode material physically supported by said crucible anode means.   
     
     
       5. A single axis combined ion and vapor source according to claim 3, --further characterized in that--   said auxiliary anode comprises anode material having a melting point differing substantially from the melting point of the anode source.   
     
     
       6. A single axis combined ion and vapor source according to claim 3, --further characterized by--   means to supply ionizable gas selectively to the vicinity of the cathode and anode,   whereby, after ionization has been commenced, gas may be shut off and ionization sustained on the vapor of anode material alone.   
     
     
       7. A single axis combined ion and vapor source according to claim 3, --further characterized by--   a plurality of anode sources, comprising a plurality of source materials; and   resistance divider means in circuit with said plurality of anode sources to provide for deposition of alloys of source materials as a function of the resistance relationships.   
     
     
       8. A single axis combined ion and vapor source according to claim 3, --further characterized by--   a plurality of cathodes; and   means mounting said plurality of cathodes external to the direct path of vapor flow from anode source to target.   
     
     
       9. A method for depositing material on a target, using a sequence or combination of vapor deposition and ionization effects, comprising the following steps: mounting the target in operative juxtaposition to a cathode and anode source in a vapor deposition and ionization environment;   establishing an ionization current between cathode and anode source in such manner that the ionization current causes heating and consequential vaporization of material from the anode source; and   selectively diverting a portion of the ionization current to an auxiliary anode to alter the heating and consequential vaporization rate of material from the anode source without altering the aggregate ionization current.